MAJOR iMac 27" display issue under Windows 7

[hundert]

Hello!
Sorry to bring this topic up... but:

The gradient issue on my imac 27 is very annoying (Just Cause 2's sky looks ugly ) so I followed the instructions above here. Except it didn't work (windows 7 says that my drivers are already updated). I decided to choose another option, the one where you can choose your drivers from a list. By mistake, I selected microsoft drivers and now I have a black screen. I guess it's the regular black screen/windows 7 problem.
Do you think I should dç the black screen method used when you install the OS (macfuse + manual delete of the driver) to solve my problem?

French here, I hope my english is not that bad.

Enjoying a lot my new iMac i7!

Hi,

you chose the wrong action which means you are wrong at "I followed the instruction"

Fist you choose "Browse my computer for driver software"
Then there is a path and a button Browse. DO NOT USE THESE but down there it says "Let me pick from a list ..." klick there, then you klick on "Hard Disk" like in instructions and there you go.

By the way, under Update Driver in the windows from the very beginning of the instructions above there is button Roll Back Driver. (It is there after you press Properties, see instructions)
You might wanna check that out.

It is a big issue and nearly everyone using bootcamp are not aware of it...

 

[TMRaven]

The website titles that image as a 16 bit gradient. Furthermore, I created a 32bit color depth document in photoshop and created a gradient on it, then saved it on an sd card and viewed the same image under windows. No drastic change in banding.

Also, I wouldn't put too much weight on internet images. Even very good png files will show banding. Only uncompressed files like tiffs won't do that.

 

[nikehair]

In Windows, you have to have the color depth set to 32-bit. I had this same problem before when it was set to 16-bit. Pretty annoying and looks cheap.

 

[iDarbert]

Update the latest ATI Catalyst Drivers (10.7) seem to work like a charm! No banding at all
Be sure to download the MOBILITY Catalyst (Choose a Laptop Graphics Card, not Desktop at the ATI Website), it will properly detect the card on the iMac and update the drivers! Whoo

This is what the driver version should be after updating the drivers

In Windows, you have to have the color depth set to 32-bit. I had this same problem before when it was set to 16-bit. Pretty annoying and looks cheap.

No, the newer drivers will give you bad gradients even if 32 bit color depth is selected

FYI I have a 27" iMac with the 4850 and the other day I downloaded and installed the latest Catalyst mobility package from the official website (10.6) under Windows 7 64 bit.

Using the Catalyst configuration app I was able to change various settings including the colors to 32bit. Every thing seems peachy. Was gaming last night and all looked beautiful. Don't seem to be any banding effects or other problems.

So I think the problems are solved touch wood? Seems to be for me anyway best I can tell.

It didn't work for me, the installer just ignored the drivers because the iMac is not supported, all it did was install the CCC.
Check your drivers version, I think it's still the old one you had before

Rolling back the drivers solved the gradient banding issues for me.

This version works

ATI Radeon HD 4850
9/23/2009
8.661.0.0

That version causes crashes for some people
(like me)

 

[Superhero360]

Hey guys,

just use the latest "Mobility Radeon" version of ATI Catalyst 10.7 drivers and everything works just fine. All my problems were solved by installing this. Just be sure to download the "Mobility Radeon" and then "Mobility Radeon HD 4000 Series".

For Windows 7 64 bit:
http://support.amd.com/us/gpudownload/windows/Pages/radeonmob_win7-64.aspx

cu
Superhero360